CutThumb got to this before I did, but I agree with his statements. The finished version of ALIEN and Bladerunner have very little to do with the original stories. While those involved deserve credit where it is due (cutting Giger out of the rest of the movie was a slap in the face), Ridley Scott is much like a chef. He took all the various elements (screenplay, script, design) and crafted them together. As amazing as the individual elements may be, they cannot compare to the final, finished product.
And to Mola Rob, I think using "franchise" is a pretty safe term. I don't believe that what was intended, certainly not with the following films, but the "Alien" idea has become a stand-alone franchise. Alien, Predator, Terminator, Star Wars; they all immediately conjure up a mental composite of all the films. When someone says "ALIEN" to me, the first thing in my mind is the Nostromo and the facehugger, but the Queen and the M41 are also there (and the wall-eye viewpoint of Alien 3). I agree that the movies, especially in the Aliens franchise are a mish-mash of differing styles, but that is more the fault of the studio than anything else.
Charlie
BTW, just want to say that I'm really enjoying the discussion. Our viewpoints may not agree, and I don't think we'll convince one another to change, but I like seeing the different perspectives.